Thanks for the reply.
It's definitely a file corruption issue. I've run the game without plugins to no avail and this is the only city affected. Obliterating the city also got rid of the problem.
I really want to keep the city as it's been built but I really don't know how to do that, if it's possible at all. I tried creating a new region with SC4M but that only lets me create an identical region without the development. If you know a way to duplicate the region while keeping the city development please let me know.

I have a massive, uncontrollable problem with water pollution.
Recently, the water pollution started rising out of nowhere, and spread across the whole tile. There doesn't seem to be any source. Water treatment plants don't do anything, and I have no idea what the cause is.
Here's the graph of the pollution:
And the eventual spread across the tile:
It increases quickly until the whole tile is red. If I demolish and dezone everything, the water pollution graph goes down, but the pollution already there doesn't go away:
The pollution goes way up as long as something is built or zoned; if there's nothing at all built, it goes down, but it shoots back up as soon as a build a single road tile, or school, or bus stop or whatever. It does the same if I zone a single tile. Subways and water pipes don't affect it, though, so it seems only surface buildings make a difference.
It only affects this single city; other cities, even those adjacent in the region, don't have the problem at all, and I tried obliterating the city (after backing it up) and the new city on the same tile didn't have this issue. I also tried building water pumps in an adjacent city and importing the water, and that water was fine, although the water pollution in this city didn't go away.
I've seen similar problems happen to other people, but not at this level. I've tried using radical water purifiers, removing my mods, duplicating the city, and every other method I can think of. I've put quite a bit of time into this city so I don't want to abandon it and I really don't know what to do. Any ideas out there?

I have two buildings I'd really like to see.
First is the Chicago Cultural Center. It was first built in 1897 as Chicago's main public library, and has since been converted into a museum and event space.
The second is San Francisco's 181 Fremont, which is a tower currently under construction.
I'd especially like to see the Chicago Cultural Center as I think there aren't nearly enough buildings of that style.

I'm starting a new city: Hartford.
I'm using a map of Boston, so there'll be some similarities, though unlike my previous city journal Alexandria (which you can see here) there's no location or history as it relates to the whole country. I'll also be using some of the same names as Alexandria, because they're good names, Brent. In this city journal, I'll be focusing on making Hartford a realistic city, rather than the best city possible, meaning sometimes I'll make a decision I wouldn't normally do.
Currently Hartford's at about 28,000 people. Here's some pictures of the initial construction of the city.

The Metro, or M, is Alexandria's subway system. With 4 lines and 30 stations, and a light rail line with 23 stations, it's unusually comprehensive for such a small city, particularly in the United States. Today it serves more than 150,000 riders each day.
Each line is named after the color as it appears on the map, except for the Brookline Shuttle, which is orange, and the Capital Connect, which is lavender. Every line is subway and elevated rail, apart from the Black Line, which is light rail. Black Line stops are marked with dashes, but stop at the regular stations as well. Sanders used to be called Pullman Street, State House used to be called Central Station, and Capitol Commons used to be called State House (I know, it's confusing). The Madison Black Line Stop is actually nearly directly in front of Sanders Station, but for realism purposes and aesthetic reasons it made more sense for the Blue Line to continue straight west.
History of the M
Starting in the late 19th century, Alexandria had a network of rail lines running across town. From the west, lines ran from southern Yorktown and the Industrial District, in what is now Kensington. These converged roughly where Sanders Station is today and rose up onto a viaduct. This continued east, stopping at a Chapman Avenue station, and crossed the Seneca River. The Yorktown line then headed northeast before curving east to College Park, while the Industrial District line turned south, descending to ground level. It had two branches: one to Industrial Park, where Acton Park is now, and one to Brownsville, via Hartford and Burlington. The tracks were extended beyond College Park on the first line to Brownsville in 1908, closely following the present alignment of the Blue and Purple Lines. The Halifax line, some of which is still in operation, ran from Halifax to Central Station, near the State House. It passed under Chapman Avenue and ran along the same route as the Capital Connect does today. This line is still in operation. Additionally, two streetcars ran through Alexandria: the downtown Chapman Streetcar, opened in 1908, and the East Side's Brown Streetcar, opened in 1912. All of these were privately owned and operated.
By the late 1940s, ridership on the train lines was declining, in part due to the rise of the automobile as the dominant form of transportation. When I-85 was completed in 1956, the lines' fate was effectively sealed, and they closed in 1959.
However, with Alexandria growing and congestion increasing, it became clear that Alexandrians needed another way to get around. Studies commenced in 1963, and in 1964 recommended the construction of a rapid transit system. The plan was finalized in 1966, calling for purchasing the old rail right of way and rebuilding viaducts on the East Side with a tunnel under I-85 as well as elevated rail in Seneca and subways downtown. The Blue and Purple Lines would take the same route and stations as the old rail lines on the East Side, but would dive underground to cross the Seneca River. They would stop at Mattapan Square, then diverge. The Purple Line would stop at Camsden Square, the State House, and Central Station. The Blue Line would stop at the planned Robert B. Reich Convention Center, Pullman Street, Ellis Street, and Wellesley Hill. The Red Line, starting at the State House, would head north, stopping at the Convention Center station, continuing north into Seneca with an eastward curve through Kensington. The Chapman and Brown Streetcars would be converted into modern light rail, with their own rights of way and a tube under the Seneca River connecting the two. Construction began on January 25, 1967.
Halifax wanted its own line, and the Green Line was added to the plan in 1968. The lines opened in phases, with the Blue Line from Brownsville to College Hill first, then the Red Line from Fisher Street to Kensington, then the Green Line from West Halifax to Yorktown, and then the Purple Line from Burlington to MacArthur. The Black Line opened next, followed by the underground section from Brownsville to Burlington, and finally the downtown subway.
The system opened with the full Green Line, the Purple Line from Brownsville to Central Station (which has since been renamed State House), the Blue Line from Brownsville to Wellesley Hill, the Red Line from Fisher Street to State House (which has since been renamed Capitol Commons), and the Black Line from Hartford to Madison.
The system has expanded several times since then. The Red Line was extended from Capitol Commons to Hartford as part of the Acton Park redevelopment in 1992; The Black Line was extended to Warren Street in 1998; the Purple Line between State House and Sanders and the Brookline Shuttle was built as part of the Capital Connect in 2015; and the Black Line branch to Newton was built in 2016.
Today, 157,000 riders take the M each day, or 38% of all trips made within the city. Alexandria has the fourth-highest transit ridership of any U.S. city. However, problems still remain: the system's proved too popular and the network is over capacity, particularly on the Red Line. The Alexandria Transit Authority is considering options to address this, but no plans have gained traction.
A Blue Line train leaving College Hill. The original brown-brick viaducts were restored in 1968.
A Black Line train on Brown Street.
A Green Line train. Yorktown residents refused a concrete viaduct, so the tracks were placed on an embankment.

Alexandria's rail service has never really been adequate. This map shows how the ATA (Alexandria Transit Authority) rail doesn't cover much of the area:
City leaders have been trying to expand the line into a full network for decades, but have been unsuccessful until recently. The project secured $1.5 billion in federal funding, allowing them to turn this:
into a reality. The network will be rebranded from ATA Rail to the Capital Connect. The Durham/Lafayette line's tracks will be doubled up, allowing trains to run on separate lines to each destination and run trains more frequently. Two tunnels, one under Wellesley Hill in western Alexandria and a much longer one under the Financial District, Brookline, the Seneca River, and Brownsville will be constructed. Viaducts and embankments will be constructed to Tyson's Corner and Charlestown. All 4 lines will terminate at the new Sanders Station on the western end of Downtown. Finally, an extension of the M's Purple line will be built to connect it with Sanders station, as well as a new Brookline Shuttle connecting Brookline station to Mattapan Square.
Here's photos of the construction.
Sanders Station under construction.
Another extraction site and the future location of the Brookline Station.
A tunnel-boring machine extraction site and the future site of the Brownsville Station.
The six tracks of the Tyson's Corner, Durham, and Lafayette lines. Here, the Tyson's Corner line turns west before tunneling under Wellesley Hill.
Preparations for constructing the Wellesley Hill tunnel.
The entrance to the completed tunnel.
Construction begins to widen the Seneca viaduct.
The new double-wide Seneca station.
The newly-built Burrell Heights station.
The finished Sanders Station.
And finally, after 3 years of construction, the first train pulls into Sanders Station.

This post is a tour of the suburbs of Charlestown, Halifax, and Seneca. First off, Charlestown.
Charlestown is a former farming community located to the east of Alexandria, on the opposite side of I-85. After I-85 and State Route 33 were built, Charlestown grew into a typical sprawling suburb.
Southern Charlestown and the Parker Street exit on SR-33.
Historic houses, built in the early 19th century.
After the rail extension to Charlestown (which I'll discuss in the next entry), several new developments have been built around the station.
Next is Halifax. Halifax has historically been (and still is) Alexandria's industrial center. Halifax is west of Alexandria and sits south of I-85 and the Halifax river.
Central Halifax and the City Hall.
The Eastern Halifax industrial zone. The parks towards the top of the picture were placed along the old rail viaduct's right of way.
After the construction of the M Green Line, apartment buildings have sprung up around the Halifax stations due to the cheap cost of land.
Finally, we have Seneca. Seneca is north of Alexandria, and it's known for its horrible traffic, due to its lack of freeways or even major arterials. Despite this, it's a fairly affluent city, and has some of the best schools in the state.
An overhead view of the city.
Ramsett Lake and the surrounding area. To the south is downtown Seneca.
Downtown Seneca. Beside the lake is the future site of the Seneca Mall. City leaders have been promoting it as a center for job growth, while residents worry it will increase traffic.

Thanks! I've found it's a lot of fun to show the development as well as the finished product.
Thanks for the suggestion on the diagonal lots. Also, it never occurred to me that the grids were in the screenshots; I'll make sure to turn those off in the future.

Today I'm showing the construction of two new developments: Norfax and Tyson's Corner, as well as the towns of Durham and Lafayette.
Norfax is a 1970s condo development located west of Alexandria between I-85 and the Halifax River. It has 13,651 units in the entire complex, plus shops, restaurants, gyms, pools, and other community facilities. Here's some pictures of the construction.
Building Tyson's Corner was both fun and difficult, since I built it on a diagonal grid.
Durham is a town of 20,000 people. It was founded in 1693 by farmers, was established as a city in 1808, and has rapidly suburbanized since World War II.
Historic Downtown Durham:
When the railroad was brought into Durham, rather than going around the hill, the builders chose just to cut a trench.
And finally, Lafayette. This far-flung suburb was built up around the old Boston Central Railway. Its streets are anything but grid-like, and its small-town feel appeals to those who want a country feel.
Lafayette Station, built in 1907.
That's it for this post. Next I'll be showing the suburbs of Seneca, Halifax, and Charlestown.

I've never been quite happy with the College Park neighborhood, and I wanted to build a modular university, so I created Greene University and the College Hill neighborhood.
Established in 1762, Greene University is one of the 8 members of the Ivy League. It has 9,432 undergraduates and 11,269 graduate students, and it's Alexandria's third-largest employer. Among its alumni are actor Matthew Holloway and former New England governor Lydia Restrepo.
Here are some pictures of the construction:

This is a quick tour of the city's most notable attractions and neighborhoods. I'll show more in future, more specific installments.
This is the New England State House. Built in 1800, it is the fifth building to serve as state house. The city government hoped that it would become a center of downtown life; however, it is rarely visited by anyone other than state employees (although there are plenty of them).
Camsden Hall, built in 1743, is the oldest surviving building in Alexandria. Originally a meeting place, the hall and the surrounding square is now a public market and events place. While most of Alexandria's historic buildings have been demolished, several blocks nearby were preserved with the establishment of the Camsden Square Historic District. Additionally, the Downtown Historic District prohibits the building of any buildings over 300 feet in the southern area of downtown Alexandria. Camsden Square is commonly used to refer to the southeastern area of downtown, Alexandria's premier shopping and nightlife district. Alexandria City Hall and the Alexandria Museum of Modern Art are located in the area.
Here we have the Central Financial District. It's one of the city's chief employment centers, and most of the banks with offices in Alexandria were located in this area, with the Bank of America being the notable exception. Since the collapse of Alexandria's banking industry in the mid-1980s, the offices have been divided between many different businesses; the companies currently occupying the most office space are Bazynga, Cloudline, and Tribune, in their namesake buildings. Despite the area's notability, not a single building over 300 feet has been built since 1994. The city government is hoping to encourage more construction in the district to pull the city out of its recession; however, transportation in the district is busy: Convention Center is the busiest station in the M system, with 3 lines running through. The city is looking for ways to provide relief, as trains running toward the station are often at capacity.
The Eastern Financial District has been a bustling employment and entertainment district since the early 1990s, when the internet companies began moving into the city. The Great American Insurance Group was located in this area until 1989, and Bank of America's world headquarters was in this area, occupying Alexandria's tallest building until 1984. In addition, the Alexandria Trojans play at Costco Field, in the center of the district. The Kings Street M station was designed as a defining feature of the area, and its design has influenced several nearby buildings.
Sometimes called the "Brooklyn of Alexandria", Acton Park is a former industrial area that has been transformed into the city's newest neighborhood. In an effort to transition away from manufacturing, the City of Alexandria purchased the large Acton Industrial Estate in 1979 with the intention to turn it into a mixed-use neighborhood. The city built new schools, parks, roadways, apartments and offices and extended the M's Red Line in order to create a vibrant community. Acton Park has, on average, the youngest residents out of every defined neighborhood, in large part due to its proximity to downtown and mixed-use development.

Location
In the southeastern corner of the state of New England is Alexandria, the state's capital and second-largest city. It sits at the mouth of both the Halifax and Seneca rivers. Boston is an hour to the north by train, and New York is two and a half to the west.
History
Alexandria was founded in 1636 by English settlers and was for many years a religious refuge. It remained a small city through the Revolution before growing rapidly in the mid-19th century, largely thanks to the banking industry. By 1920, over 150,000 people lived in Alexandria. Most of the banks left the city in the 1970s and 80s, but the emerging technology companies took over, driving a period of innovation and growth- the population grew from 250,000 to 325,000 during the 1990s alone.
Alexandria Today
Today, Alexandria is a center for innovation, rivaling even Silicon Valley on the West Coast. It currently is home to 460,000 people. Unfortunately, the city was hit hard by the 2008 financial crisis. Every bank that still had offices left the city, and unemployment reached 11%. The city is slowly making its way back up, but it will take time before Alexandria is the financial powerhouse it was.
Transportation
Alexandria's unique geography, with its downtown surrounded on three sides by water, has made typical American transportation planning difficult. As a result, there is only one freeway, Interstate 85, which runs around the East Side and bypasses Downtown to the north. To make up for this, Alexandria built a rapid transit system, the M (short for Metro), which opened in 1973. The combination subway-and-elevated rail network is unusually comprehensive for such a relatively small city.